This invention relates to a fluid-cooled jacket and, more particularly, to a fluid-cooled jacket for an air-swept distributor for particulate solid materials.
Fluidized bed reactors, such as combusters, steam generators, and gasifiers are well known. In these arrangements, air is passed through a bed of particulate materials, including a fossil fuel such as coal and an adsorbent for the sulfur generated as a result of the combustion of the coal, to fluidize the bed and to promote the combustion of the fuel at a relatively low temperature. When the heat produced by the fluidized bed is utilized to convert water to steam, such as in a steam generator, the fluidized bed system offers an attractive combination of high heat release, high sulfur adsorption, low nitrogen oxide emissions, and fuel flexibility.
The particulate fossil fuel combusted in these fluidized bed reactors is supplied to the reactor by a distributor which transports the particulate fuel from the fuel supply to the fluidized bed reactor. The particular design of the distributor controls the flow characteristics of the fuel.
Utilization of fluidized bed reactors has increased with their ability to combust lower heating value fuels, which often have a relatively higher moisture level and a lower temperature softening point. The higher moisture level in the fuel causes increased adhesiveness, which makes these fuels difficult to transport. Therefore, air-swept distributors have been utilized, since they provide efficient, low-cost, low-maintenance transportation of these relatively high moisture-level fuels.
However, when the temperature of the air-swept distributor causes the fuel to be heated above its softening point, the adhesive qualities of the fuel are dramatically increased, which severely curtails fuel transportation through the distributor. Also, if the air-swept distributor is heated to such a high temperature that the fuel will stick and then burn in the distributor, the distributor would be damaged.